Multi-nuclear pulse Fourier-transform nuclear magnetic resonance (FT-NMR) techniques will be applied to the study of "metastable" metabolites of the anticancer drug cyclophosphamide, namely cis- and trans-4-hydroxycyclophosphamide and 3,4-dehydrocyclophosphamide as yet undetected metabolites of cyclophosphamide will also be studied by means of direct synthesis and FT-NMR methods. Stable isotopes for FT-NMR analysis will be used where applicable.